[PATCH] x86_64: fix last_tsc calculation of PM timer
From: "Jan Beulich" <jbeulich@novell.com> The PM timer code updates vxtime.last_tsc, but this update was done incorrectly in two ways: - offset_delay being in microseconds requires multiplying with cpu_mhz rather than cpu_khz - the multiplication of offset_delay and cpu_khz (both being 32-bit values) on most current CPUs would overflow (observed value of the delay was approximately 4000us, yielding an overflow for frequencies starting a little above 1GHz) Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -68,7 +68,7 @@ int pmtimer_mark_offset(void)
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offset_delay = delta % (USEC_PER_SEC / HZ);
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rdtscll(tsc);
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vxtime.last_tsc = tsc - offset_delay * cpu_khz;
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vxtime.last_tsc = tsc - offset_delay * (u64)cpu_khz / 1000;
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/* don't calculate delay for first run,
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or if we've got less then a tick */
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